


Scientific Method

by SenkoWakimarin



Category: Batman v Superman: Dawn of Justice, DC Extended Universe, Justice League (2017)
Genre: Alien Biology, First Time, First Time Blow Jobs, M/M, Plot What Plot/Porn Without Plot, Xenophilia
Language: English
Status: Completed
Published: 2019-01-10
Updated: 2019-01-10
Packaged: 2019-10-07 13:25:17
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,689
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17366678
Author URL: https://archiveofourown.org/users/SenkoWakimarin/pseuds/SenkoWakimarin
Summary: The thing is, Bruce has wanted this for a long time, for a lot of reasons. And the reasons may have changed, but the want sure hasn't.





	Scientific Method

**Author's Note:**

  * For [susiecarter](https://archiveofourown.org/users/susiecarter/gifts).
  * Inspired by [Packing Nonstandard Equipment](https://archiveofourown.org/works/15674424) by [susiecarter](https://archiveofourown.org/users/susiecarter/pseuds/susiecarter). 



> This fic follows, with permission, SusieCarter's 'Packing Nonstandard Equipment'. I recommend reading that first for context, it's probably my very favourite SuperBat fic in existence. 
> 
> My first (possibly only) attempt at these characters. Hopefully not terrible lmao.

The thing is, whatever else he is, Bruce has always been something of a scientist. The scientific approach to problems worked, over and over it yielded better results than impulsively following whatever drive might seize him.

So discovering that Kryptonian physiology was in several significant ways different from human was easy enough to work with. They had to move with some measure of slowness, carefulness, make sure that nothing they did ended up harming the other, but it was entirely doable. He, for better or worse, liked Clark. He liked kissing him, liked making him feel good, and Kryptonian anatomy might be distinctly different but it was obviously, in every way that mattered for their purposes, compatible.

What must it have been like for Clark, growing up, figuring out all the ways he was different, all the things he’d have to do to pass as, if not _normal_ , then at least _typical._ Average. Someone who wouldn’t stand out, who could have a chance to blend into the crowd despite being, in every way, extraordinary. Mentally, it must have affected him quite deeply -- Bruce finds his frown tightening at the memory of Clark, with such abject sincerity, calling his own body _disgusting_.

Ridiculous. It was anatomy. Different from a human’s, certainly, but no less pleasing.

As eager as Bruce is the drill that particular fact into Clark, he still is compelled to do this right. And by right, he means scientifically. Uncharted territory, after all, means taking things slow enough to establish a baseline of normalcy, and make sure they don’t stumble into a way to hurt one another.

They’d been lucky, really, so far. Bruce’s impulsive enthusiasm had already yielded several encouraging facts. For example: Bruce could make Clark come -- something that, thus far, Clark hadn’t seemed able to make himself do. Which is interesting (hot), _very interesting,_  especially because Bruce hadn’t really ever considered the possibility of Clark begging him for _anything_ , much less…

Well.

It was interesting.

The tendrils -- _tentacles_ , he supposes, if he wants to call a spade a spade -- are prehensile, free moving, eagerly seeking pleasure through touch. They curl and writhe around Clark’s fingers squeezing back when he strokes through them, hands swallowed and tangled in the squirming mess of his groin. Objectively, it should be at the very least strange. It is distinctly inhuman, and yet there’s something entirely transparent about the nature of what he’s witnessing.

“Bruce,” Clark pants, and that’s interesting too, because as far as Bruce understands, Clark doesn’t really need to breathe, but he’s still made breathless. “I don’t… think it’s gonna work, it’s, it’s _different_ , with you, when you, please, I…”

This, really, is Bruce’s favourite part of this particular experiment. The way Clark seems tangled up in himself, the tendrils red and taut around his fingers, his attempts to talk stilted and raspy. He sounds right on the absolute edge, and Bruce sits a little straighter, watching.

“Didn’t work… last two times, Bruce, you… you said...”

Clark’s words dry up, eyes fluttering, and his whole body seeming to draw up with sympathetic tension as his collective dicks engorge in their weirdly smooth uniform ripple,  and then… nothing. Clark relaxes slowly, fingers sliding loose from where he’s been gripping himself, dicks finally relaxing, barely moving now.

Finally, Bruce shifts closer, moving on his knees across the bed, to press hands to Clark’s shoulders and kiss him. And there is nothing, really, nothing in the world that compares to that, to kissing a _breathless_ Clark Kent until he’s licked his way into Bruce’s mouth, giving up on the pretense of breathing all together.

Only when Bruce’s heart is thundering in his ears, lungs starting to burn, does Clark let him go. Even then he’s reluctant to sit back on his heels.

“Twice is a coincidence,” Bruce finally intones. “Three times proves there’s a pattern.”

The colour on Clark’s cheeks darkens, and honestly a man built lke that has no business being so easily adorable. He says, “I hate to burst your bubble on this, but I’m not so innocent that I haven’t touched myself before.”

“Not while I was watching, you hadn’t,” Bruce says smoothly, eyes creasing as he smiles.

Clark rolls his head on his shoulders to look at Bruce more directly, leveling him with a stare that’s amused and arch all at once. It’s very nearly a challenge, but Bruce maintains the space he’s put between them. “You staring at me like I’m on your exam table ready for the knife isn’t exactly the sexiest situation I’ve been in.”

The thing _is_ , Bruce wears a lot of masks. They slip on and off as he needs them, sliding into place. He wears so many, sometimes it’s hard to remember when he doesn’t _need_ to put one on. The pouty little smile that slips onto his face is more Bruce Wayne than Batman, a mask that flits into place before he can help it.

“Well,” he says, reaching for one of Clark’s warm hands, pulling him toward the edge of the bed as if he has a hope in hell of moving the man if he doesn’t want to be moved. “Then I guess I should make it up to you, huh?”

To say Bruce hasn’t thought about this before would be an obvious lie. He’d thought of it before he ever saw Clark without clothes on, the idea of going on his knees for the man first a worrying distraction and then idle masturbatory fantasy. Early fantasies painted Clark as demanding, forceful, because Bruce had always found… something, in fear and loss of control. He liked the idea of Clark manhandling him.

As they’d come to work together more closely, started getting to know one another, the fantasy had… shifted. Clark would be gentle, worried about keeping his strength in check. It would frustrate Bruce, but charm him in a way he didn’t choose to examine too far, until Bruce _made_ him lose some of that control.

Now, knowing exactly what he’s working with, Bruce has a feeling that this will be one of those exceptional moments where reality bests fantasy completely.

Clark makes a vague questioning noise, but moves agreeably to sit on the edge of the bed when Bruce steps off it and pulls him there. He’s so good, so kind, he has so much control, and it all comes to bear in the fact that, if Bruce didn’t _know_ that Clark was letting himself be pulled across the bed, Bruce would be able to fool himself into thinking he had really moved him there.

It’s this consideration, which Bruce is fairly positive comes to Clark completely naturally, not a put-on, not a _mask_ , that makes Bruce so helplessly fond of him. Clark is genuine. This is an immutable a fact as the certainty of death.

And really, see, the thing is, Bruce likes making people feel good. At the core of who he is, that’s most of what he wants to do. It’s difficult, so difficult, between the masks and the expectations and the complications of who he has chosen to be. He often -- very often -- gets it wrong, and more often, he must elect to act in a way that seems harsh to yield better results for the people he wishes to help. In his closest personal relationships, he is still forced to push others away, because it’s the only way to steer them towards something kinder, something better.

On his knees, hands resting carefully on Clark’s spread thighs, Bruce lets Clark turn his face up to meet those brilliantly blue eyes. He couldn’t push Clark if Clark didn’t want to be pushed. Couldn’t pull him, either. He is allowed a certain measure of control, but in the end, Clark is stronger. His kindness and patience may be the only light strong enough to stand up to the dark that sometimes falls over Bruce.

“Are you sure,” Clark says, and this close Bruce can hear the slide of flesh over flesh as those tendrils respond to his proximity. From anyone else, this might have been a challenge, a dare, but in those eyes Bruce sees a different sort of war. Want versus fear. Even now, Clark is worried about what Bruce will think of him, worried Bruce will suddenly find all of this simply too weird and call and end to it.

This smile is all Bruce, no mask. This is just him, laid bare for Clark, letting him in because he can trust him. “If you’re uncomfortable, I’m willing to stop. Personally, I’m _very_ interested in proceeding.”

Clark, sweet and genuine Clark, bites distractedly on his lower lip and seems to weigh something. “I’m just… there’s a lot and…”

Sometimes the Bat creeps up on Bruce. The drive, the aggression, the want for a challenge. His smile sharpens to something Clark might have seen once or twice under the cowl, but the purr of his voice is more Wayne. Balance between the two dramatic ends of public personae, and somewhere in the middle it’s just him, just Bruce.

“I’m sure that, between the two of us, we can manage something effective.”

The fingers on his jaw slip away finally, and Bruce maintains eye contact just a moment longer, hoping to drive home the point that he’s here because he wants to be, not because he’s _obligated_.

It’s undeniably, utterly different than any sexual act Bruce has ever performed before. Academically, he’d known it was bound to be, but there’s knowing without doing and knowing in practice.

When he dips his head, he tightens his fingers on Clark’s thighs, mouthing at the nest of tendrils already writhing to feel for his face. They skirt along his jaw, over his neck, warm and firm, a boneless grip no less strong for the flexibility. He kisses and licks at them, moving along the collective lengths, and when the first one pushes at his mouth he eagerly lets it in. It’s not like tongue kissing, and it’s not like sucking a dick or sucking on fingers. It’s entirely new and different, unique but certainly pleasant.

Bruce has had plenty of interesting, non-standard sexual encounters. Just by the virtue of the path he’d elected to follow to create the Wayne public persona, it was necessary that he would have experienced a wide variety of sexual acts. He’s become quite good at feigning enjoyment and reading a partner to maximize their pleasure even if he himself is getting none.

This is not a situation that requires that particular skill, though he goes into it thinking it might be.

No, it’s not as… aggressive as he’d thought it might be, which gives him cause to wonder just how much control Clark can exercise over the fleshy tubules. They had seemed so eager under his hands, around his dick, every other time Bruce had touched them. Here though, they’re careful, pushing into his mouth a few at a time, curling over each other to tease his tongue. They taste like warm, soft flesh, drier than a dick should be. Clark never tastes of sweat, not really, and this is no different; he tastes clean. That’s the best analysis Bruce’s mind is willing to cough up at this point; Clark tastes clean and his myriad dicks are carefully pushing into Bruce’s mouth, as many as can fit now, the gentleness that had defined the initial interaction slowly fading.

Honestly, the thing about it _is,_  Bruce has always had a sort of _fondness_ for giving oral sex. There’s a lot of complicated things that go into that particular proclivity, he’s sure, but the nearest he can define it to is that he enjoys the trust displayed when someone is willing to let him do this, bare themselves to his hands and mouth when it would be easy as anything to hurt them quite badly.

So Bruce has been scrupulous in testing things with Clark since that first night because when he got around to this, he didn’t want to run into any more than the normal level of discomfort. Teasing Clark that it was for the sake of science was well and good (anything that made Clark turn that particular shade of red was well and good, honestly), but there had been logic behind it. Making sure the released spores weren’t hazardous to him in any immediate way had been important. Making sure that Clark had the self control to stop even at the cost of his own pleasure, also important. Measuring Clark’s refractory period and continued sensitivity level after excessive stimulation; important.

Getting to watch Clark get himself as close to orgasm it seemed he could through manual stimulation three times in one night was a bonus in checking these things, true.

Bruce has wanted to do this for so long and now that he’s getting too, and it’s very nearly more than he knows how to handle. His mouth has never been so full, and he can still feel more of Clark pressing at the edges of his mouth, vying for position, trying vainly to make room where there is none. They fill his mouth so completely he can barely move his tongue, but they courteously have yet to try for his throat, for which he’s grateful. Those that don’t fit inside live up quite well to his imagination, feeling blindly over his face so he ends up kneeling there before Clark, eyes shut, head tilted at just such an angle so allow the tentacles in his mouth maximum wriggle room.

What’s that colloquialism… more than a mouthful is a waste? Bruce would distinctly beg to differ by this point; his face is covered in hot, swollen lengths, clinging anywhere they can, feeling carefully along his jaw, his hairline, the shell of his ear, holding him, petting him.

It’s bizarre and quintessentially strange, and the first time Bruce tries to move, trying to take the collective in his mouth in deeper, they all tense, holding him, so he moans softly and then Clark, as if in answer, breathes his name.

There’s a certain sound to a man experiencing a certain pleasure for the first time, and Bruce is greedy to hear more of that from Clark. It’s quite obvious that no one has ever done this for him before -- when would he have ever allowed the opportunity, so dead set on hiding himself. There is no precedent for how to do this, and Bruce is already certain that if Clark comes in his mouth it’s going to be a very new kind of unpleasant, but god does he want it anyway.

He wants to hear his name on Clark’s lips louder, like it’s the only thing he can think, the only thing he wants. He flexes his tongue and tries to duck his head again, and the tendrils seem to get the message this time, drawing him down and writhing gently against his tongue, letting him press them against the roof of his mouth and swallow as best he can around them. The resulting sound is thick and wet in his ear, and he shivers, suddenly very aware of how hard he is.

“Bruce, I, I, oh god, I want…”

Bruce can only imagine how that sentence might end, but it trails of in a series of throaty, eager gasps as he works with the mass of tentacles in his mouth to start pulling them into his throat.

He can’t really smirk with his mouth and now his throat so incredibly full, but he risks cracking one eye open so he can look up as Clark curls over him, hips twitching forward (is there a penetrative aspect to Kryptonian coupling? He has to assume so, judging by the way Clark seems to instinctively want to get deeper) one hand clutching at his hair.

Clark’s eyes are closed, his lips parted, wet as if he’s run his tongue over them recently, and he’s panting softly again, trying to find words but managing only these stuttering little exhales. It’s a treasure of an expression, Clark at the very edge of self control, trying to keep himself from claiming Bruce’s mouth with any force. Trying to keep gentle, to make sure Bruce can pull away if he needs.

So Bruce, of course, makes sure to take a good few deep breaths through his nose, and then slides down farther, filling up his throat now, until there’s so much pressing his esophagus open it very nearly hurts.

“Bruce, it’s… it’s too… oh _God_ , Bruce, please, _please_ I need…”

The thing is, Bruce never imagined to hear Clark begging him this way, never _really_ thought he’d hear Clark begging him in _any_ circumstance, and he wants _more_.

Quick learners, the tendrils on his face continue to pet across his skin lightly, stroking and caressing, but they don’t try to hold him when he sucks back along the length in his mouth. They’re touching him everywhere that they can reach and Bruce just wants more. Clark’s hand in his hair provides a little more resistance, but he keeps pulling back and Clark doesn’t clutch or pull him into place, just keeps his hand resting there as if unsure what else to do.

There’s a sort of mindless, mindful state Bruce finds himself sliding into during fellatio, attentive and eager but also letting his body move the way it wants. Just sort of doing what seems to feel good for both of them, so Clark is groaning this wounded, pleased sound as he takes him in his throat again, and Bruce can fumble his way into his own underwear, closing a hand over his dick.

It feels good.

It feels absurdly good. Bruce’s hot face touched everywhere by hotter, prehensile dicks, Clark's fingers gripping and relaxing rhythmically in his hair, drool eking its way from the corners of his stretched lips, smeared over his face before it can roll down his chin. His own cock, hard and dripping in his fist, brought to his own brink just by having Clark (or as much as him as will fit) in his mouth.

Clark gasps, the thigh still under Bruce’s free hand tensing up as if he’s fighting the urge to thrust, or maybe stand. He remains sitting, but Bruce braces himself, remembering how the tendrils had swollen that first time, under his hands, filling up before they dispersed. He wonders at the biology of it, stealing a fresh breath before his mouth and throat are suddenly so full his jaw feels ready to crack.

The heat and weight in his mouth, on his tongue, filling him, is so different and so good. He wants, striping his own cock in a rush now, to feel Clark come undone for him.

But that restraint is monumental, and Clark never pulls his hair, never thrusts reflexive and sharp down his throat. He goes suddenly, impossibly still, as if it’s the only defense he can think against the urge to do any of that, and the tentacles on his face draw firm and almost too hot to his skin, clamping down, holding him like the rest of Clark refuses to.

Everything is heat and pressure and the kind of sexual discomfort where you know intrinsically that you’ll be sore later but in the moment everything feels too good to change anything, and everything seems to grow a little tighter as the tendrils draw up more, a sort of pulse going through them and it’s so much, too much, and Bruce can feel tears welling up in his eyes, slipping from tightly shut lids, and then his mouth and throat are suddenly too dry, tingling, so much, too much.

He can smell it, a vaguely sour, sort of sweet smell. It doesn’t _taste_ like mushroom, or mildew, or any kind of spore Bruce has ever inadvertently breathed in. His mouth begins to water intensely even as Clark is easing himself out, and the taste -- sort of like a more bland Pixie Stick, he thinks -- coats his whole mouth. He swallows reflexively, uttering a little whine as Clark leans away from him, finally, finally able to breathe without restriction again. He comes just like that, on his knees beside the bed, Clark staring at him like _he’s_ the marvel here.

“You… I didn’t expect you to… I’m sorry?”

And it’s so patently ridiculous an apology, so sincere and sweet because he understands what Clark is trying to apologize for, but it’s utterly unnecessary when Bruce has very obviously enjoyed himself immensely. All of which Bruce will say as soon as his throat feels a little less raw, as soon as his lips stop tingling and his mouth is done watering in reflex to the sudden jolt of… ejaculated spore.

Instead of speaking, he moves carefully to his feet, letting Clark steady him when he seems unsteady at first, and pushes himself into Clark's lap, resting his head on one broad shoulder, kissing the smooth, unmarred skin as gently as he would if it were possible to bruise. Clark settles a hand against the back of his neck, another on his waist, and just holds him.

Because the thing is, scientific method or no, carefully approached or no, this was a momentous sort of occasion, a whole new step in their relationship, and they’re both a little dizzy with it. Even if it had been meticulously outlined and gone through with the brutal efficiency of a mission, it would still be emotionally enormous.

More, Bruce doesn’t know for a certainty how Clark feels about him -- fond, certainly, trusting, obviously, but how deep? How far? -- but he knows that he cares for Clark so deeply that it aches, that it frightens him in a way that once only the dark had.

He had beaten his fears before, knows he can master them again, and the thing is, he could push away or pull closer, but ultimately, he can’t move Clark if Clark doesn’t want to be moved. That’s as comforting as it is terrifying, and Bruce thinks there’s maybe a necessity to that balance for him.


End file.
